This invention relates to a resin encapsulated semiconductor device and to a method for its fabrication, and more specifically to a resin encapsulated semiconductor device capable of being fabricated in a thin format.
Semiconductor devices are widely used in various types of electronic products, consumer products, automobiles, integrated circuit cards, and the like. One feature of the semiconductor device which is important in many of these applications, and especially in such applications as the integrated circuit card, is the small size of the semiconductor device.
The semiconductor devices which are used in those various applications are usually packaged by either one of two methods. In one method, a semiconductor device die is placed in a package which is then individually mounted on a circuit substrate. In an alternate method, the semiconductor device die itself is mounted directly on the circuit substrate and then is usually provided with a protective encapsulation structure. The first mentioned method has the advantages that the device die is sealed in and protected by the package. The packaged device is easy to test, handle, and install and the encapsulating package provides the desired degree of protection against the environment. In contrast, the second described method in which the device die is connected directly to the substrate minimizes the area required by the die and thus allows a very high packing density. In this method, however, the device die is less easily handled and tested and is more subject to undesirable effects of the environment.
In selecting either of the above mentioned packaging techniques, it is necessary to compromise in the characteristics of the semiconductor device and the way it is utilized. In addition, either method requires that the semiconductor device be packaged on the interconnecting substrate such as a PC board, and thus has a problem of preventing the reduction in the thickness of the substrate so that the semiconductor device cannot be used in an application such as an IC card which requires an extremely thin substrate.
Thus a semiconductor device and a method for its fabrication were needed which would overcome the limitations of the foregoing semiconductor devices and methods.